The volcanism of Italy is due chiefly to the presence, a short distance to the south, of the boundary between the Eurasian Plate and the African Plate. Italy is a volcanically active country, containing the only active volcanoes in mainland Europe (while volcanic islands are also present in Greece, in the volcanic arc of the southern Aegean). The lava erupted by Italy's volcanoes is thought to result from the subduction and melting of one plate below another.
Three main clusters of volcanism exist: a line of volcanic centres running northwest along the central part of the Italian mainland (see: Campanian volcanic arc); a cluster northeast of Sicily in the Aeolian Islands; and a cluster southwest of Sicily around the island of Pantelleria, in the Mediterranean's Strait of Sicily. Sardinia has had a totally separate geological history from that of the rest of Italy, where several cycles of volcanic activity occurred, the last of which ended at the beginning of the Pleistocene, but currently hosts only permanently extinct volcanoes. [1]
Due to their position within densely populated areas, Etna and Vesuvius have been included in the list of "Volcanoes of the Decade", a global list of volcanoes to be kept under closer surveillance. [2] In particular, the "Volcanoes of the Decade" is a list drawn up by International Association of Volcanology and Chemistry of the Earth's Interior, as part of a United Nations project, which includes, overall, 16 volcanoes distributed all over the world. [2]
Italy was the first country to exploit geothermal energy to produce electricity. [3] The high geothermal gradient that forms part of the peninsula makes it potentially exploitable also in other regions; research carried out in the 1960s and 1970s identified potential geothermal fields in Lazio and Tuscany, as well as in most volcanic islands. [3]
Four of Italy's volcanoes have erupted in the last one-hundred and fifty years:
At least 10 other volcanic centres have seen eruptions in historic times. In order of the most recent eruptions, they are:
In addition to the volcanoes on land, there are three submarine volcanoes in the seas surrounding Italy, in particular in the south-eastern Tyrrhenian and in the Strait of Sicily:
In Italy there is also a large number of geological structures due to extinct volcanic centres. It is possible to group these volcanoes into various categories:
The volcanic system of Somma-Vesuvius is generally characterized by explosive eruptions. The most widely-known is the one that destroyed the Roman cities of Pompeii, Herculaneum, Stabiae and Oplontis in 79 AD, causing thousands of victims. It is estimated that this eruption had a Volcanic Explosivity Index (VEI) equal to 5, and is considered the archetype of Plinian eruptions, which are named after Pliny the Younger, an eyewitness of the event. [30] [31]
Scholars have discovered that previously Vesuvius had given rise to even more violent Plinian eruptions, [32] the last of which was that of the pumice of Avellino about 3,900 BP (estimated to have a VEI of 6). After 79 AD there were no more plinian eruptions, but at most sub-plinian. The most important were that of 472 AD [33] (whose ash reached Constantinople) and that of 1631, which killed thousands of people (due to pyroclastic flows and lahars), [34] ) and which was taken as a reference by Protezione Civile for the drafting of evacuation plans in the event of future eruptions. [35] Due to this eruptive history, and the very high population density in the Metropolitan City of Naples, Vesuvius is considered one of the most dangerous volcanoes in the world. [36]
Unlike Vesuvius, the nearby Phlegraean Fields are not made up of a single large volcanic edifice, but are a vast volcanic field within which numerous eruptive vents have opened, often different from eruptions. [37] The only eruption in historical times, which generated Monte Nuovo and Lake Avernus, was of low intensity, and was preceded by a period of quiescence that lasted more than 3,000 years (before which there was a long sequence of close eruptions). [38] However, the Phlegraean Fields are capable of producing violent eruptions, which earned them the title of supervolcano.
The most famous was that of the Campanian Ignimbrite eruption, which occurred about 40,000 BP, considered the most severe ever to occur in the Mediterranean area, having a VEI equal to 7, and which probably had effects on the climate worldwide. [39] Only slightly less intense was that of the Neapolitan yellow tuff, which occurred about 15,000 BP. [40] There are also indications of a third large-magnitude eruption, which probably occurred 29,000 BP. [41] For this reason, the Phlegraean Fields are also closely monitored by the Vesuvius Observatory.
They are also characterized by numerous secondary volcanic phenomena, of which the best known is the Phlegraean bradyseism, which in the second half of the 1900s led to the evacuation of entire districts of the city of Pozzuoli.
Etna is characterized by an almost continuous eruptive activity, and, unlike Vesuvius, the eruptions of Etna tend to be effusive, with lava flows that can come from both the summit craters and side openings. These eruptions almost always do not cause high damage, but there are exceptions. The largest effusive eruption of Etna in historical times took place in 1669, when the lava buried numerous villages reaching the sea near Catania, with a flow up to 17 km long. This eruption completely changed the landscape of the area, but due to its effusive nature there were no victims associated with the eruption. [42]
Another eruption of similar magnitude occurred in 396 BC, when the lava flows, reaching the sea, hindered the advance of the Carthaginian army of Himilco during the Greco-Punic wars (as described by Diodorus Siculus). [43] A few dozen deaths were recorded in Bronte in the eruption of 1843, due to a phreatic explosion due to contact between the lava and a source of water. The last highly destructive eruption occurred in 1928, when the lava buried the town of Mascali. [44] In the 1979 eruption, a sudden explosion caused nine deaths and 23 injuries in a group of tourists on excursion, and in that same eruption the last official order to evacuate an inhabited centre was issued due to an eruption of Etna. [45]
The great explosive eruption of 122 BC, a Plinian event, which caused serious damage to the Roman city of Catania, which for this reason was exempt from paying taxes to Rome for a decade, was completely different. A further explosive eruption, of a sub-Plinian type, occurred in 44 BC. This eruptive history, associated with the high population density of the Metropolitan City of Catania (but with a less problematic situation than that of Naples), therefore requires continuous surveillance of the volcano.
Stromboli is one of the most active volcanoes in the world, with almost persistent activity for at least 2,000 years, which is why it was nicknamed the "lighthouse of the Mediterranean". Usually this activity consists of a continuous degassing, interspersed with small bursts of low intensity, at temporal distances that can vary from a few minutes to a few hours, a type of eruption that is defined precisely as Strombolian. [6]
About 1–2 times per decade, lava can overflow from the summit craters, forming flows that can also reach the sea. These flows usually go towards the north-western area of the island, in the so-called Sciara del Fuoco (a depression shaped like a horseshoe, formed about 6,000 BP, [46] ) away from the inhabited settlements. At irregular intervals, Stromboli can give rise to much more violent explosions than normal, called paroxysms, [47] which can instead cause damage to the population.
On 11 September 1930, what is considered the most violent eruptive event of the volcano in the last 13 centuries, [48] occurred with a massive fallout of volcanic material on the inhabited centre of Ginostra and the formation of a pyroclastic flow outside the Sciara del Fuoco. In total, there were four deaths and numerous buildings destroyed. The most recent paroxysmal events occurred on 3 July and 28 August 2019, [49] with the former explosion causing the death of a hiker. [50] In these eruptions, pyroclastic flows able to flow over the sea for a few hundred meters have also been observed. [51]
A further source of danger about Stromboli is the risk of landslides (often in correspondence with the paroxysms), both aerial and submarine, capable of causing tsunami waves. The last event of this type occurred on 30 December 2002, when the wave did damage to coastal buildings. [52] An underwater landslide event of greater proportions could have caused the tsunami in the Gulf of Naples in 1343. [53]
The geography of Italy includes the description of all the physical geographical elements of Italy. Italy, whose territory largely coincides with the homonymous geographical region, is located in southern Europe and comprises the long, boot-shaped Italian Peninsula crossed by the Apennines, the southern side of Alps, the large plain of the Po Valley and some islands including Sicily and Sardinia. Italy is part of the Northern Hemisphere. Two of the Pelagie Islands are located on the African continent.
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. The process that forms volcanoes is called volcanism.
The Aeolian Islands, sometimes referred to as the Lipari Islands or Lipari group after their largest island, are a volcanic archipelago in the Tyrrhenian Sea north of Sicily, said to be named after Aeolus, the mythical ruler of the winds. The islands' inhabitants are known as Aeolians. The islands had a permanent population of 14,224 at the 2011 census; the latest official estimate is 15,419 as of 1 January 2019. The Aeolian Islands are a popular tourist destination in the summer and attract up to 600,000 visitors annually.
Mount Vesuvius is a somma–stratovolcano located on the Gulf of Naples in Campania, Italy, about 9 km (5.6 mi) east of Naples and a short distance from the shore. It is one of several volcanoes forming the Campanian volcanic arc. Vesuvius consists of a large cone partially encircled by the steep rim of a summit caldera, resulting from the collapse of an earlier, much higher structure.
Lipari is a comune including six of seven islands of the Aeolian Islands and it is located in the Tyrrhenian Sea off the northern coast of Sicily, Southern Italy; it is administratively part of the Metropolitan City of Messina. Its population is 12,821, but during the May to September tourist season, the total population may reach up to 20,000. It is also the name of the biggest island in the archipelago, where the main urban area of the comune is located.
Vulcano or Vulcan is a small volcanic island belonging to Italy in the Tyrrhenian Sea, about 20 km (12 mi) north of Sicily and located at the southernmost end of the seven Aeolian Islands. The island is known for its volcanic activity and contains several volcanic calderas, including one of the four active volcanoes in Italy that are not submarine. The English word "volcano", and its equivalent in several European languages, derives from the name of this island, which derives from the Roman belief that the tiny island was the chimney of Vulcan, the Roman god of fire. In November 2021, 150 people were evacuated from the island's harbour area due to increased volcanic activity and gases; an amber alert had been issued in October 2021 after several significant changes in the volcano's parameters.
Mount Etna, or simply Etna, is an active stratovolcano on the east coast of Sicily, Italy, in the Metropolitan City of Catania, between the cities of Messina and Catania. It is located above the convergent plate margin between the African Plate and the Eurasian Plate. It is one of the tallest active volcanoes in Europe, and the tallest peak in Italy south of the Alps with a current height of 3,403 m (11,165 ft), though this varies with summit eruptions. For instance, in 2021 the southeastern crater reached a height of 3,357 m, but was then surpassed by the Voragine crater after the summer 2024 eruptions.
Volcanology is the study of volcanoes, lava, magma and related geological, geophysical and geochemical phenomena (volcanism). The term volcanology is derived from the Latin word vulcan. Vulcan was the ancient Roman god of fire.
Stromboli is an island in the Tyrrhenian Sea, off the north coast of Sicily, containing Mount Stromboli, one of the four active volcanoes in Italy. It is one of the seven Aeolian Islands, a volcanic arc north of Sicily, and the mythological home of Aeolus.
A volcano observatory is an institution that conducts research and monitoring of a volcano.
The Phlegraean Fields is a large caldera volcano west of Naples, Italy. It is part of the Campanian volcanic arc, which includes Mount Vesuvius, about 9 km east of Naples. The Phlegraean Fields is monitored by the Vesuvius Observatory. It was declared a regional park in 2003.
Plinian eruptions or Vesuvian eruptions are volcanic eruptions marked by their similarity to the eruption of Mount Vesuvius in 79 AD, which destroyed the ancient Roman cities of Herculaneum and Pompeii. The eruption was described in a letter written by Pliny the Younger, after the death of his uncle Pliny the Elder.
In volcanology, a Strombolian eruption is a type of volcanic eruption with relatively mild blasts, typically having a Volcanic Explosivity Index of 1 or 2. Strombolian eruptions consist of ejection of incandescent cinders, lapilli, and volcanic bombs, to altitudes of tens to a few hundreds of metres. The eruptions are small to medium in volume, with sporadic violence. This type of eruption is named for the Italian volcano Stromboli.
The Campanian volcanic arc is a volcanic arc that consists of a number of active, dormant, and extinct volcanoes in the Campania region of Italy. The Campanian volcanic arc centers on the bay of Naples and includes:
Several types of volcanic eruptions—during which material is expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behavior has been observed. Some volcanoes may exhibit only one characteristic type of eruption during a period of activity, while others may display an entire sequence of types all in one eruptive series.
Marsili is a large undersea volcano in the Tyrrhenian Sea, about 175 kilometers (109 mi) south of Naples. The seamount is about 3,000 m tall; its peak and crater are about 450 m below the sea surface. Though it has not erupted in recorded history, volcanologists believe that Marsili is a relatively fragile-walled structure, made of low-density and unstable rocks, fed by the underlying shallow magma chamber. Volcanologists with the Italian National Institute of Geophysics and Volcanology (INGV) announced on March 29, 2010, that Marsili could erupt at any time, and might experience a catastrophic collapse that would suddenly release vast amounts of magma in an undersea eruption and landslide that could trigger destructive tsunamis on the Italian coast and nearby Mediterranean coastlines.
A multi-component gas analyzer system (Multi-GAS) is an instrument package used to take real-time high-resolution measurements of volcanic gases. A Multi-GAS package includes an infrared spectrometer for CO2, two electrochemical sensors for SO2 and H2S, and pressure–temperature–humidity sensors, all in a weatherproof box. The system can be used for individual surveys or set up as permanent stations connected to radio transmitters for transmission of data from remote locations. The instrument package is portable, and its operation and data analysis are simple enough to be conducted by non-specialists.
The 2002 Stromboli tsunami was caused by a volcanic eruption in the Aeolian Islands of Sicily, located on the Tyrrhenian Sea. In May 2002, one of the island's two active volcanoes, called Stromboli, entered a new phase of explosive activity that was initially characterized by gas and ash emission from the summit craters. On 30 December 2002, the seismic network recorded two large collapses of a huge portion of the Sciara del Fuoco, which resulted in the tsunamis. The first landslide was around 13:15 and the second one around 13:23, which lasted for 5–7 minutes. The event caused damages on the eastern coast side of Stromboli and Panarea. These tsunamis have been considered the most violent ones to have struck Stromboli in the past 100 years.
According to The World Factbook, the main natural phenomena posing a threat in Italy at a regional level are landslides, mudflows, avalanches, earthquakes, volcanic eruptions, floods and, in Venice, subsidence.
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